Roller tappet pumps of this type are used, for example, in internal combustion engines, in particular in diesel internal combustion engines, for generating high pressure in the fuel supply. High-pressure pumps in internal combustion engines may be driven, for example, by a camshaft to impose a predefined stroke movement on high-pressure cylinders of the high-pressure pump. The raising of the particular cams of the camshaft is transmitted in these cases via the roller tappets to the high-pressure pistons of the high-pressure pump.
A roller tappet is known from EP 0 074 458, having a cylindrical guide body, which has two bearing parts for retaining an axle, on which a roller is mounted so it is rotatable. The bearing parts have two bearing cavities open on top, in which the axle ends of an axle are laid, on which the roller is mounted so it is rotatable. A recess in the roller tappet is implemented in such a way that the roller is axially fixed.
A roller tappet having a tappet, which carries an axially and radially guided roller, is known from DE 101 57 076 A1. The tappet has a roller shoe, into which the roller is introduced so it is rotatable with axial play. A roller shoe of the tappet accommodates the roller in a recess. The recess of the roller shoe tapers toward a lower edge of the roller shoe in such a way that the roller is prevented from falling out of the roller shoe.
A roller tappet is known from DE 199 09 418 A1, having a main body, a roller, and a roller axle for the roller mounted in the main body. The angular range in which the roller axle is mounted in the main body is at most 180°. Furthermore, means are provided which fix the roller axle in relation to the main body in the axial direction of the main body and which comprise a sheet metal cage, which is clamped on the main body and has tabs which wrap around partial areas of the axle.
A piston pump for high-pressure fuel supply is known from DE 197 29 793, having a tappet which has a reversible roller on its radial internal area, which is supported so it may roll against a driveshaft of the piston pump in the area of its protrusions around the circumference.
A roller tappet having a cage retainer is known from DE 44 21 535 A1, the roller tappet comprising a roller shoe in which a roller is guided in a formfitting way, via which the roller tappet presses against a cam ring. The roller shoe has a retention element for fixing the position of the roller.
An elastic roller tappet is known from DE 32 47 026 A1, having a roller on whose front faces a coaxially situated depression is implemented, to thus generate the elasticity of the roller boundary area.